Lifetime Resilience of Bridges Under Single and Multiple Hazards: Emphasis on Earthquake and Corrosion

Design and assessment of structures have been geared towards addressing the most dominant hazard at the location of interest. In general, single hazard approaches underestimate risk. Therefore, the possibility of structures experiencing multiple independent or interacting hazards of different types during their lifetime needs to be considered. The design methodology of bridges must shift towards a more comprehensive approach of addressing multiple hazards to ensure adequate performance under different mechanical and environmental stressors. Quantification of the reliability and risk associated with damage to individual bridges under multiple hazards can help in prioritizing retrofit activities for bridges in a network. Significant advances have been accomplished in the field of earthquake engineering. However, there is a need to promote further research for developing concepts and methods in order to design resilient bridges and assess the resilience of existing bridges and bridge networks in a life-cycle context. Resilience emphasizes the impact of infrastructure damage, failure and societal recovery under extreme hazards with a low probability of occurrence and high consequences. An infrastructure system needs to include resilient and adaptive capabilities for ensuring its long-term performance. This keynote paper provides an overview of life-cycle design and assessment methodologies of bridges under multiple hazards with an emphasis on earthquake and continuous deterioration. Several important performance indicators such as risk and resilience necessary to be implemented into the practical design and assessment are introduced. Finally, the concepts and methods presented are illustrated in case studies on bridge networks under seismic and corrosion hazards.